Download MISCELLANEOUS NOTES 1. A Glimpse on Human Genome

Our Nature (2003) 1
MISCELLANEOUS NOTES
1. A Glimpse on Human Genome
bacteria, plants, and fruit flies. Today an
expanded array of tools available for the
direct study of human genetics attracts
scientists from around the world to
collaborate to identify and study every
human gene.
The Human Genome Project began in
earnest in the United States in 1990 with the
expansion of funding from the National
Institutes of Health (NIH) and the
Department of Energy (DOE). The first
director of the U.S. program was American
Biochemist James Watson. Many nations
have official human genome research
programs as part of this collaboration,
including the United Kingdom, France,
Germany, and Japan. In a separate project
intended to speed up the sequencing process
and commercialize the results, Celera
Genomic, a privately funded Biotechnology
Company, used a different method to
assemble the sequence of the human
genome. Both the public consortium and
Celera Genomic completed the first phase of
the project, and they each published a draft
of the human genome simultaneously,
although in separate journals, in February
2001 (Fasman 2002).
The project goals are to identify all the
approximate 30,000 genes in human DNA,
determine the sequences of the 3 billion
chemical base pairs that make up human
DNA, store this information in databases,
improve tools for data analysis, transfer
related technologies to the private sector,
and address the Ethical, Legal, and Social
Issues (ELSI) that may arise from the
project. Knowledge about the effects of
Cell is a basic unit of life. That is the
smallest structures, capable of basic life
processes, such as taking in nutrients,
expelling waste, and reproducing. All the
instructions needed to direct their activities
are contained within the chemical DNA.
Any organism’s complete set of DNA
(chromosomes) including its gene is
genome. The set of chromosomes contain
certain number of genes, which are different
in every genus and species. Chromosome is
microscopic structure found within cells that
carries the DNA, the hereditary material that
influences
the
development
and
characteristics of each organism. DNA
carries hereditary information in a form that
can be copied and passed intact from
generation to generation. A gene is a
segment of DNA. There are numerous genes
in an organism and each of these genes are
responsible for expressing the different
characters, e.g. hair color, eye color, hair
texture etc.
Since the earliest days of plant and
animal domestication, around 10,000 years
ago, humans have understood that the
characteristic traits of parents could be
transmitted to their offsprings. The first to
speculate about how this process worked
were Greek scholars around the 4th century
B.C., who promoted theories based on
conjecture or superstition. Some of these
theories remained in favor for several
centuries. The scientific study of genetics
did not begin until the late 19th century.
Until the 1980s, genetic researchers focused
their work on the fundamental genetic
processes in simpler organisms, such as
58
Our Nature (2003) 1
collaboratively, pooling its resources and
skills, keeping its focus on the goal, and
making its results available to all as they
were acquired. The Human Genome Project
has achieved the following progress until
February 12, 2001.The human genome
contains 3164.7 million chemical nucleotide
bases (A, C, T, and G).The average gene
consists of 3000 bases, but sizes vary
greatly, with the largest known human gene
being dystrophin at 2.4 million bases. The
total number of genes is estimated at 30,000
to 35,000, much lower than previous
estimates of 80,000 to 140,000 that had
been based on extrapolations from gene-rich
areas as opposed to a composite of generich and gene-poor areas. The order of
almost all (99.9%) nucleotide bases is
exactly the same in all people. The functions
are unknown for over 50% of discovered
genes. The human genome's gene-dense
"urban
centers"
are
predominantly
composed of the DNA building blocks G
and C. In contrast, the gene-poor "deserts"
are rich in the DNA building blocks A and
T. GC- and AT-rich regions usually can be
seen through a microscope as light and dark
bands on chromosomes. Chromosome 1 has
the most genes (2968), and the Y
chromosome has the fewest (231). The ratio
of germline (sperm or egg cell) mutations is
2:1 in males vs. females. Researchers point
to several reasons for the higher mutation
rate in the male germline, including the
greater number of cell divisions required for
sperm formation than for eggs.
The Human Genome Project will be
ended in the third- and final plan
“September 30, 2003” with providing
numerous achievements to the mankind.
After completing the Human Genome
sequence we will be able to know about all
genes function, position, composition,
identification
and
regulation.
The
DNA variations among individuals can lead
to revolutionary new ways to diagnose,
treat, and someday prevent the thousands of
disorders that affect us. Besides providing
clues to understanding human biology,
learning about nonhuman organisms' DNA
sequences can lead to an understanding of
their natural capabilities that can be applied
toward solving challenges in health care,
energy
sources,
agriculture,
and
environmental cleanup. To help achieve
these goals, researchers also are studying
the genetic makeup of several nonhuman
organisms. These include the common
human gut bacterium Escherichia coli, the
fruit fly, and the laboratory mouse.
Discovering approximately 25,000 to
35,000 human genes (the human genome)
make them accessible for further biological
study, and determine the complete sequence
of the 3 billion DNA subunits (bases)
(Wolfsberg et al. 2001). In February 2001 a
“rough draft” of the DNA sequence of the
human genome was published. The draft
provided a basic outline of 90 percent of the
human genome. Researchers expect that a
finalized version of the complete sequence
of the human genome will be finished by
2003, two years earlier than originally
projected.
With
the
simultaneous
description of a second draft of the human
genome by Celera Genomics, scientists now
have a more detailed blueprint of the human
genetic code. Scientists were surprised to
learn that the actual number of human genes
is far lower than expected—only about
31,000 genes compared to the predicted
100,000 genes. This number is a little more
than twice the number of genes found in the
fruit fly (Fasman 2002). It is the
achievement of a coordinated effort
involving 20 laboratories and hundreds of
people around the world. It reflects the
scientific community at its best: working
59
Our Nature (2003) 1
successful. In the next 15 to 20 years, more
effective drugs will be developed, and
doctors will test individual genetic profiles
against panels of drugs available for a
specific condition and choose the treatment
with the greatest potential benefit.
Today, some 100,000 people die each
year from adverse reactions to drugs, and
millions of others must bear uncomfortable
or even dangerous side effects. As genes
and other DNA sequences that influence
drug response are identified, we can expect
the number of toxic responses to drop
dramatically and most side effects to be
eliminated. One of the most difficult issues
is determining the proper balance between
privacy concerns and fair use of genetic
information (Anon 2002). The growing
number and use of genetic tests has many
worried about discrimination due to
inappropriate access to, and use of, private
genetic information. Most protections,
whether in terms of employment or health
insurance discrimination, are at the state
level. If there is not strict legislation for fair
uses of genetic information, we may face
some unpleasant consequences unless
society makes some hard choices. Based on
genetic information, employers may try to
avoid hiring workers they believe are likely
to take sick leave, resign, or retire early for
health reasons (creating extra costs in
recruiting and training new staff), file for
workers' compensation, or use healthcare
benefits excessively. Some employers may
seek to use genetic tests to discriminate
against workers--even those who do not and
may never show signs of disease--because
the employers fear the cost consequences.
Genetic predisposition or conditions can
lead to workplace discrimination, even in
cases where workers are healthy and
unlikely to develop disease or where the
genetic condition has no effect on the ability
availability of a reference human DNA
sequence
is
a
milestone
toward
understanding how humans have evolved,
because it opens the door to large-scale
comparative studies. The major impact of
such studies will be to reveal just how
similar humans are to each other and to
other species (Pääbo 2001). The sequencing
of the human genome heralds a new age in
medicine, with enormous benefits for the
general public. For example, it will allow
scientists to identify all of the genes
contributing to a given disease state, leading
to a more accurate diagnosis and precise
classification of disease severity. In
addition, healthy patients can know the
diseases for which they are at risk, giving
them the opportunity to make beneficial
lifestyle changes or to take preventive
medications to protect their health.
Understanding the genetic bases of heritable
diseases also will allow researchers to
develop therapeutics at the molecular level,
resulting in better treatments with fewer side
effects (Jeffords and Daschle 2001). The
identification of all human genes, for
example, will help improve diagnosis of
most inherited diseases. The research also
will help uncover the mechanisms that make
some people more susceptible to certain
diseases, such as heart disease, stroke, and
several kinds of cancer, and pave the way to
more effective therapies and preventive
measures, scientists believe. A virtually
complete list of human gene products will
give us a vast repertoire of potential new
drugs. Our medical record will include our
complete genome as well as a catalogue of
single base-pair variations that can be used
to accurately predict our responses to certain
drugs and environmental substances. This
will permit us to be treated as a biochemical
and genetic individual, thus making medical
interventions more specific, precise, and
60
Our Nature (2003) 1
information bureaus, without their consent.
Rapid progress in genome science and its
potential applications make biology will be
the foremost science of the 21st century.
Technology and resources generated by the
Human Genome Project and other genomics
research are already having a major impact
on research across the life sciences.
Dil Kumar Subba
to perform work. Insurers can still use
genetic information in the individual market
in decisions about coverage, enrollment, and
premiums. Insurers can still require
individuals to take genetic tests. Individuals
are not protected from the disclosure of
genetic information to insurers; plan
sponsors
(employers),
and
medical
Central Campus of Technology, Dharan
Emal:[email protected]
Jeffords, J. M. and T. Daschle 2001. Genome Era in
Political Issues. Science.291 (5507): 1249-1251.
Pääbo, S. 2001. The Human Genome and Our View
of Ourselves. Science. 291(5507): 1219-1220.
Wolfsberg, T. G., J Mcentyre and G. D. Schuler
2001. Guide to the draft human genome.
Nature 409: 824-826
References
Anonymous, 2002. Human genome project
information, Human Genome Program, U. S.
Department of Energy Office of Science, Office
of Biological and Environmental Research
Fasman, K. H. 2002. Microsoft® Encarta®
Encyclopedia.
2. Avifauna of Tinjure Forest, Eastern Nepal
(Lophophora leucomelana) and Satyr Tragopan
(Tragopan satyra). There is no specific
geographical barrier in between the adjoining
areas so that the movement of wildlife and birds
within these areas is possible. The area is
covered with magnificently beautiful and
splendid Rhododendron jungle intermixed
mainly with oak and other tree species such as
Magnolia spp., Castanopsis spp., Abies
spectabilis, Betula utilis, Taxus baccata with
different kinds of shrubs, herbs, climbers,
epiphytes and grasses. In these regions, survey
of bird was conducted in 1997-1998. A total of
73 bird species belonging to 23 families were
recorded. Birds were observed in dense forest,
degraded forest, bamboo grooves, scrub and
open habitats.
Birds were identified (Table 1) with the help
of available literature (Fleming et al. 1979,
Inskipp and Inskipp 1985, Ali and Ripley 1995).
Tinjure Forest, one of the ecologically
important regions, lies on the eastern mid-hills of
the country at a distance of about 9 km. from
Basantapur bazaar of Tehrathum district. Its
altitude ranges between 2400-3010 m and
covers 22 sq. km. lying in between Basantapur
and Chauki (Rai 1998). Basantapur is a small
market located on the boarder of Sankhuvasabha
and Terhathum district. Infrastructure of
development, such as road and communication
has turned this area into the trading centre for
Terhathum, Sankhuvasabha and some parts of
Bhojpur district. Large amount of Lokta’
(Daphne spp.) and medicinal plants are collected
there. The area is mostly steep with forested
slopes and ridges. The broad-leaved deciduous
moist forest mostly covers the area and the lower
canopy is composed of Rhododendron spp.,
Quercus spp., and Daphne spp. It is rich in
biodiversity and provided the home to various
indigenous and rare birds like Kalij Pheasants
61